The recent development in the filed of semiconductor devices has been dramatic, and the areas of application of semiconductor devices have been continually expanding. Simultaneously with the development in semiconductor chips which may be considered as the cores of the semiconductor devices, significant improvements have been made to the packaging of semiconductor chips.
For instance, various proposals have been made to improve the security and increase the convenience of pre-paid cards such as magnetic cards for public telephones, personal identification cards such as vehicle operators licenses, and passes for train services.
Such IC cards may be characterized as consisting of a circuit board having a conductor circuit, a semiconductor chip mounted on the circuit board, optional electronic components such as capacitors, a device for receiving and transmitting signal into and out of the circuit board, and a casing for covering the circuit board as described in "Information Processing Handbook" compiled by Shadan Hojin Joho Shori Gakkai, published by KK Ohm, first edition, May 30, 1990, pages 302 to 304.
With regard to the structure of the IC card, it is also known, as illustrated in FIG. 8, to attach a semiconductor chip 2 to a card base board 1 by using a bonding agent 10, and connect the connecting terminals of the semiconductor chip and the connecting terminals of the card base board with bonding wire 11 as described in "IC Card" compiled by Shadan Hojin Joho Denshi Joho Tsushin Gakkail published by KK Ohm, first edition, May 25, 1990, page 33.
The thickness of the semiconductor chip contemplated herein is approximately from 200 to 400 .mu.m , and the semiconductor chip is not highly resistant to bending stress so that there is a need to control the stress that is applied to the semiconductor chip. Therefore, the size of the semiconductor ship has to be limited, and/or the casing has to be made of a material resistant to bending stress.
As disclosed in Japanese patent laid-open (kokai) publication No. 3-87299, it is also known to make an IC card by preparing an IC module including an extremely thin LSI which is prepared by grinding the LSI to a reduced thickness while leaving the driver devices intact, and mounting this IC module in a recess provided on the surface of the package. An intrinsic problem with the IC card using an extremely thin LSI mounted on a relatively thick base board is a lack of reliability due to the fact that the thin LSI is vulnerable to the large tensile and compressive stresses that are applied to the front and rear surfaces of the LSI chips as the card base board undergoes a bending deformation.
It was proposed in Japanese patent laid-open (kokai) publication No. 7-99267 to place the thin IC in a middle part of the thickness of the IC card as a method to overcome such a problem. According to this technology, as shown in FIG. 9, the semiconductor chip 2 is mounted on the printed circuit board 1 with the connecting terminals of the semiconductor chip and the connecting terminals of the printed circuit board exposed in a common plane, and the connecting terminals of the semiconductor chip and the connecting terminals of the printed circuit board are electrically connected with each other by printed electroconductive paste 12.
However, according to the method in which a semiconductor chip is mounted on a printed circuit board with the connecting terminals of the semiconductor chip and the connecting terminals of the printed circuit board exposed in a common plane, and the connecting terminals of the semiconductor chip and the connecting terminals of the printed circuit board are electrically connected with each other by printed electroconductive paste, when the IC card is generally subjected to a bending deformation, stress tends to concentrate in the boundary between the connecting terminals of the semiconductor chip and the connecting terminals of the printed circuit board, and cracks may generate in the electroconductive paste with the result that a high risk of electric disconnection exists.